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US5001622A
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Enhanced real-time control of PWM inverter
Assignee: Sundstrand Corp
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Filing: 1990-05-10
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Granted: 1991-03-19
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Expires: 2010-05-10
Abstract
Abstract In a pulse width modulated inverter, the fit of a selected switching angle is monitored by counting zero crossings in a neighborhood of the function ##EQU1## for each harmonic of interest. If the fit is bad, a switching angle is moved to improve the fit.
Inventors
- 👤 Maurice A. Kirchberg, Jr.
- 👤 Alexander Cook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:31
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/539; H02M7/5395
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
70 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter comprising the steps: integrating the product of the inverter output and each harmonic of interest over a period equal to the fundamental of the inverter a.c. output; monitoring for each harmonic the crossing of a predetermined value of said product within a predetermined neighborhood extending on each side of a midpoint.
Claim 2
Independent Claim
70 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter comprising the steps: integrating the product of the inverter output and each harmonic of interest over a period equal to the fundamental of the inverter a.c. output; monitoring for each harmonic the crossing of a predetermined value of said product within a predetermined neighborhood extending on each side of a midpoint.
Claim 3
Dependent Claim
47 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 1 wherein said neighborhood is an interval of one half the a.c. fundamental output divided by the number of the harmonic which forms the product.
Claim 4
Dependent Claim
53 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 2 wherein said midpoint is a point where said product for each harmonic would pass through said value if the harmonic content for said each harmonic is within an acceptable level.
Claim 5
Dependent Claim
53 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 1 wherein said midpoint is a point where said product for each harmonic would pass through said value if the harmonic content for said each harmonic is within an acceptable level.
Claim 6
Dependent Claim
29 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 1 wherein said predetermined value is zero.
Claim 7
Independent Claim
96 words
A method of monitoring and adjusting the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter comprising the steps: integrating the product cf the inverter output and each harmonic of interest over a period equal to the fundamental of the inverter a.c. output; monitoring for each harmonic the crossing of a predetermined value of said product within a predetermined neighborhood extending on each side of a midpoint; adjusting the time of occurrence of a switching point in the pulse width modulated waveform when the crossings do not meet a predetermined criteria.
Claim 8
Independent Claim
96 words
A method of monitoring and adjusting the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter comprising the steps: integrating the product cf the inverter output and each harmonic of interest over a period equal to the fundamental of the inverter a.c. output; monitoring for each harmonic the crossing of a predetermined value of said product within a predetermined neighborhood extending on each side of a midpoint; adjusting the time of occurrence of a switching point in the pulse width modulated waveform when the crossings do not meet a predetermined criteria.
Claim 9
Dependent Claim
47 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 6 wherein said neighborhood is an interval of one half the a.c. fundamental output divided by the number of the harmonic which forms the product.
Claim 10
Dependent Claim
53 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 7 wherein said midpoint is a point where said product for each harmonic would pass through said value if the harmonic content for said each harmonic is within an acceptable level.
Claim 11
Dependent Claim
42 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 8 wherein said predetermined criteria is that the number of crossings is equal to the number of harmonics of interest.
Claim 12
Dependent Claim
29 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 6 wherein said predetermined value is zero.
Claim 13
Dependent Claim
42 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 6 wherein said predetermined criteria is that the number of crossings is equal to the number of harmonics of interest.
Claim 14
Dependent Claim
53 words
A method of monitoring the harmonic content of the output of a pulse width modulated d.c. to a.c. inverter as in claim 6 wherein said midpoint is a point where said product for each harmonic would pass through said value if the harmonic content for said each harmonic is within an acceptable level.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-03-18 | 1994-09-17 | 1995-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-18 | 1998-09-17 | 1999-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-18 | 2002-09-17 | 2003-03-19 | $7700.00 | Window Closed / Lapsed |